OLI Engine with RadFrac and FraChem

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How to enter specifications from FraChem Column to RadFrac Column

When using OLI Engine in Aspen Plus, it is recommended that the end user enables OLI models from Aspen Libraries and use OLI's FraChem column. FraChem and RadFrac perform similar duties as 2-3 phase fractionation for a single column, model absorbers or strippers. When using FraChem it is imperative that you have OLI Chemistry model loaded in Aspen Plus.

See this for "How to use OLI Engine in Aspen Plus" : Installing_the_OLI_Engine_for_Aspen_PLUS

The procedure below assumes that you have the exact same FraChem and radFrac coulmns. Meaning that you have the same number of stages, feeds etc. For the purpose of this document, the examples are created using Getting Started in Aspen Plus user guide.

Below are the images for how the columns look like in the Aspen Simulation Environment. Please note that FraChem is an OLI ONLY Model Column and RadFrac is the Aspen equivalent of that unit operation. FraChem.png




FraChem Screens

OLI's FraChem column has the following specification options:


See this for examples on RadFrac and FraChem in Aspen-OLI : OLI_Engine_9.2_in_Aspen_Plus_User_Guide

Creating an environmental variable on your machine

In order to get the specifications from the FraChem column you need the LIS file with temperature and pressure inputs. In order to see that file, you need to create an environmental variable on your machine.

Profile 1.png

Go to advanced system setting

Profile 2.png

Click on Environmental Variables:

Profile 3.png

Create a new variable


It should show up in the user variables for your machine as shown below:

Profile 4.png

Click OK.

Locating and opening an LIS file

Run your FraChem Column example again.

Go to the same location as your FraChem example file:

Locate the RADF.LIS file there.

Lis 1.png

Typically the LIS file will have estimates as follows:

Lis 2.png

Copy this information and place it on the clipboard.

Locating and opening an Input file

When you open your simluation bkp file with the RadFrac column, go to the Home tab and locate the Input button on the toolbar as shown below:

Inpu file.png

Appending the input file for an OLI Chemistry RadFrac example

Open the input file for the already created chemistry model bkp file with a RadFrac Column. Scroll down to the bottom of the Input file where block parameters are:

Radfrac input.png

Paste the data from the clipboard that you have copied before.

Paste the data below the block parameters and above the design spec information if you have any.

After pasting your input file should like follows:

Copy paste.png

Make sure you are in the all files mode when you save your input file. Type the inp extension manually at the end of the file name and click Save/


Save the input file as an inp file at the same location as the bkp file.

Open the .inp file

Right click and open the .inp file from the folder containing the bkp file with the Aspen Version that you need.


This should open similar content as your FraChem example file. Only difference is all your FraChem data is now in RadFrac Specification tabs.

Example files

When you run your RadFrac modified example now, you will notice that under Convergence and Estimates, you have exact same estimates as your FraChem column:


Please find the example for the file with the FraChem column, the LIS file and the RadFrac column inp file in this zip folder.

File:Chlorinescrubber chapter3.zip

Running from Command Line

To Run the inp file from command line instead Aspen has the option of Customize Aspen Plus :